Fasting And Orthodoxy

Οὐδὲν ὀνίνησι νηστεία τοὺς ὑγιέσι μὴ προσέχοντας ὅροις· ὅσῳ γὰρ τοῦ σώματος ἡ ψυχὴ προτερεύει, τοσοῦτον πολιτείας δόγματα προκρίνεται εὐσεβείας.  Ἅγιος Ἰσίδωρος Του Πηλουσιώτου, Βιβλιον Πρῶτον, Ἐπιστολὴ ΣΜΔ', Ἡρμινῳ Κομητι Source: Migne PG 78.332b

Fasting is to no profit at all if one does not take care to keep oneself within healthy limits; for as much as the soul is superior to the body, so holy doctrine is superior to the state of life. Saint Isidore of Pelusium, Book 1, Letter 244, to Count Herminos